电子束辐照技术提高玉米蛋白粉酶解效果

    Improving effect of enzyme hydrolysis of corn gluten meal by assistant of electron beam irradiation

    • 摘要: 为了研究玉米蛋白粉的酶解关键技术和利用电子束辐照技术辅助提高玉米蛋白粉的酶解效果,该研究以蛋白质质量分数为79.4%的玉米蛋白粉为原料,以水解度(degree of hydrolysis,DH)和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picryl-hydrazyl, DPPH)清除率为衡量指标,借助单因素和响应面试验设计方法,在优选碱性蛋白酶可控酶解制备玉米抗氧化肽的最佳工艺参数基础上,研究了不同辐照剂量的电子束辐照处理对玉米蛋白粉酶解效果的影响,并利用场发射扫描电镜检测技术分析电子束辐照前后玉米蛋白粉表面形态的变化。研究发现:当碱性蛋白酶的酶解温度为50℃、酶解pH值为8.6、酶与底物浓度比为9.13%时,玉米蛋白粉的水解度可达40.26%±0.23%;所制备的玉米抗氧化肽的DPPH清除率为70.74%±0.41%;若采用辐照剂量为3.24 kGy进行电子束辐照处理玉米蛋白粉时,则其水解度可达到49.17%±0.42%,其DPPH清除率可达73.03%±1.02%;经场发射扫描电镜检测分析得知,被辐照处理后的玉米蛋白粉表面凹凸程度增加,完整性下降。研究结果可为玉米精深加工产业和玉米抗氧化肽的深入研究提供理论参考。

       

      Abstract: Abstract: In this study, the key technology of enzymatic hydrolysis of corn protein powder and the improvement of enzyme effectiveness with the electron beam irradiation technology were researched. Corn gluten meal (mass fraction of 79.4 %) was used as raw material. Alacalase was used to hydrolyze corn gluten meal, and degree of hydrolysis (DH) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) inhibition were used as testing indexes. In order to develop and optimize conditions for the enzymatic hydrolysis reaction, we investigated three variables: enzyme solution temperature, pH value, and ratio of enzyme to substrate. One-factor-at-a-time (OFAT) and response surface metrology (RSM) experiment were used to optimize the conditions for hydrolysis. Based on the optimized results, the influences of different electron beam irradiation doses on the DH and DPPH inhibition of corn gluten meal were studied. The irradiation dose rate was 1.08 kGy/s, the irradiation time were 0, 1, 2, 3, 4, 5, and 6 seconds, the irradiation doses were 0, 1.08, 2.16, 3.24, 4.32, 5.4 and 6.48 kGy. And the microcosmic surface features of corn gluten meal in three irradiation doses (0, 3.24 and 6.48 kGy) by electron beam irradiation treatment were analyzed by scanning electron microscope (SEM). The results of OFAT showed that, the DH reached the highest value 37.89%±2.89% when the enzyme solution temperature was 60℃, and the DPPH inhibition reached the highest value 58.45%±2.07 % when the temperature was 40℃. The DH reached the highest value 40.81%±0.8% when the pH value was 9, and the DPPH inhibition reached the highest value 72.93%±0.96% when the pH value was 6. The DH reached the highest value 38.31%±0.8 % when the ratio of enzyme to substrate was 12%, and the DPPH inhibition reached the highest value 67.07%±0.83% when the ratio of enzyme to substrate was 2%. The results of RSM test showed that, the optimized parameters of enzyme hydrolysis were: enzyme solution temperature was 50℃, pH value was 8.6, ratio of enzyme to substrate was 9.13%. On these conditions, the DH value of corn gluten meal was 40.26%±0.23%, and the DPPH inhibition of corn antioxidative peptides (CPS) was 70.74%±0.41%. In the electron beam irradiation experiment, the optimize irradiation dose was 3.24 kGy, with the DH of 49.17%±0.42% and DPPH inhibition of 73.03%± 1.02%. The SEM results showed that compared with the blank sample, the smoothness of corn gluten meal powder with irradiation decreased, and the specific surface area was increased. The results provide a reference for corn processing industry and also for further studies on corn antioxidant peptides.

       

    /

    返回文章
    返回